**HD 219134 d**
**Definition:**
HD 219134 d is an exoplanet orbiting the star HD 219134, located approximately 21 light-years from Earth in the constellation Cassiopeia. It is part of a multi-planet system and is classified as a super-Earth.
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## Overview
HD 219134 d is one of several planets discovered around the K-type main-sequence star HD 219134. The star is relatively close to the Solar System, making its planetary system a subject of interest for studying exoplanet characteristics and potential habitability.
## Discovery
The planet was detected using the radial velocity method, which measures variations in the star’s motion caused by gravitational interactions with orbiting planets. Its discovery contributed to the understanding of compact multi-planet systems around nearby stars.
## Characteristics
HD 219134 d is classified as a super-Earth, indicating it has a mass larger than Earth’s but smaller than that of ice giants like Neptune. Its orbital period and distance from the host star suggest it is unlikely to be within the habitable zone, but its exact composition and atmosphere remain subjects of ongoing research.
## Significance
The proximity of HD 219134 and its planetary system provides valuable opportunities for detailed observation and study. HD 219134 d, along with its sibling planets, helps astronomers explore planetary formation and dynamics in systems different from our own.
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**Meta Description:**
HD 219134 d is a super-Earth exoplanet orbiting a nearby K-type star approximately 21 light-years away. It is part of a multi-planet system studied for insights into planetary formation.